Orobanche uniflora

Oneflowered cancer root


The Basics

Taxonomy: Kingdom - Plantae (plants). Subkingdom - Tracheobionta (vascular plants). Superdivision - Spermatophyta (seed plants). Division - Magnoliophyta (flowering plants). Class - Magnoliopsida. Subclass - Asteridae. Order - Scrophulariales. Family - Orobanchaceae (Broom-rape family). Genus - Orobanche L. Species - Orobanche uniflora L.

Ecology: One flowered cancer root (also called one-flowered broomrape) is a native annual found from Vancouver Island and Southern British Columbia south to California, east to Florida and Newfoundland. This species is often found in damp woods and thickets, and open places from lowlands to moderate elevations in mountains.


Stem subterranean, fleshy, white, brittle, covered with long (to 3 cm) waxy, glabrous scales; sparsely (1-7) branched. Flowers borne on elongate, glandular pubescent pedicles to 14 cm tall usually arising at or below ground level. Flowers 1.5 cm long, 0.3 cm wide, corolla white to pale blue, sub-regular, the 5 lobes shorter than the arcuate tube, median lower lip with tow yellow guidelines. Stigma anterioposterially lobed. Calyx sub-regular, 0.5 to 1 cm long the 5 lobes longer than the tube. Capsule ovoid 0.7 cm thick, the persistent corolla usually present.

Unique Characteristics

A fascinating aspect of the biology of this species is expressed by is brownish stems and minute scale-like leaves. This plant does not contain chlorophyll, and is dependant on other plants to produce nutrients. The species is parasitic on a wide array of species to include the genus Sedum and members of the families Saxifragaceae and Asteraceae. Given the species wide distribution, this is somewhat expected.

This plant is considered a pest or noxious weed in several states in the U.S.


Orobanche uniflora flowers in April to June. The fuirt ripens shortly after the flowers open. The seeds are small and the longevity in soil is still in debate.

Species Distribution


USDA Plants Database
USDA, NRCS. 2016. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.

USFS Plant Database
DeLay, Chantelle, and Terry Miller. "Plant of the Week."; Johnston Ridge Observatory | US Forest Service

The Orobanchaceae of Virginia
Musselman, L. J. (1982). The Orobanchaceae of Virginia. Castanea, 266-275.

Seed Production and Dispersal in the Orobanchaceae
Joel, D. M. (2013). Seed production and dispersal in the Orobanchaceae. In Parasitic Orobanchaceae (pp. 143-146). Springer, Berlin, Heidelberg.